Hi there. I did a search and I found several topics with people with exact the same trouble on their cars and the same codes, but none of them had a solution.

I have a 2006 A4 1.8T Cabriolet (it's actually my sister's, lol) and it suddenly started to shatter and run idle like crap, even tho you can drive it it feels like the car is loosing vacuum because once you let the gas pedal off it starts misfiring. The codes are p0300, p0301, p0302, p0303, p0304. Pretty much misfires on all cylinders.

My sister took it to the dealer and they wanted like $1000 to fix it, so she told em to give her a break, so they gave her the list of components they were gonna replace to fix the issue. ($80 plastic pipe, $75 check valves.... please...)

I located the parts on the car, mostly hoses, plastic pipes and check valves, so I removed everything from the car, checked them all and all seemed to work properly, the hoses were fine, no leaks, the valves weren't broken or cracked, they properly worked one way and sealed perfectly on the other. One plastic pipe was a bit cracked and I replaced it, so pretty much every part the Audi dealer gave me I checked them and they were working properly. Installed everything back and the car is still running like crap

They said it was definitely a vacuum issue at the dealer, so I tried to spray Carb Cleaner all over the vacuum lines, and areas where I thought it might be leaking vacuum, but it never got better, the car idled like crap.... What can I do???

Please help!!!!!

 

Wow, not even one reply??